Faune aquatique et qualité de l′eau des puits et sources de la région d′Oum-El-Bouaghi (Nord-Est algérien)

Abstract

A recent study, performed in the region of Oum-El-Bouaghi, North-Eastern Algeria, aimed at showing the possible relationships between the water quality of wells and springs and the diversity of the aquatic fauna which occurs in these habitats. To this end, the water quality and the fauna were regularly investigated in several stations (16 wells and 2 springs) selected in the region. The stations were chosen considering visible differences related to both their fauna and also some evident characteristics i.e. water table depth, nature of geological substratum, protection and human use, so that it was possible to expect certain diversity. The main physicochemical characteristics of water were measured and a Principal Component Analysis (PCA) was performed with the mean values of each variable. The PCA indicated an appreciable spatial variation of water quality related to the values of some hydrological variables and clearly showed four groups of stations: a first group of 11 wells located in the downstream part of the study area, where water exhibited a high level of nitrogenous and phosphoric ions revealing water pollution. In contrast, another group of 5 wells located more upstream and where the water, containing only very low concentrations of nitrogenous and phosphoric ions, is of good quality. Finally two other groups are well separated and include only one spring each, where water is also of good quality. Likewise, the fauna of each station was regularly sampled. The total faunal richness of stations was poorly correlated with water quality but, in contrast, the specific richness of the stygobiontic fauna (the subterranean species living in groundwater), and moreover the abundance of these stygobiontic species decreased significantly in case of water pollution. Thus the stygobiontic fauna and especially the peracarid crustaceans appear to be good indicators of water quality in the studied wells and springs. © 2011 EDP Sciences, SETE.